1. Field of the Invention
This invention relates generally to a system and method for warning vehicle drivers of potential hazardous road conditions and, more particularly, to a system and method for warning vehicle drivers of potential hazardous road conditions that uses a vehicle-to-vehicle communications system and in-vehicle sensors, where the sensors detect the hazardous road conditions and the probability of the detected condition from a vehicle is aggregated with the probability of the detected condition from other vehicles to provide a distributed aggregation operator that is transmitted to vehicles approaching the road condition.
2. Discussion of the Related Art
Traffic accidents and roadway congestion are significant problems for vehicle travel. Providing continuous traffic information to a vehicle driver is available in today's vehicles through, for example, XM radio or wireless Internet. One of the challenges in current traffic information systems is that the information is not in real-time, which means that there may be a considerable delay between collecting the traffic information and presenting it to a particular vehicle driver where sometimes the information may be outdated or misleading.
Vehicular ad-hoc network based active safety and driver assistance systems allow a wireless vehicle communications system to transmit messages to other vehicles in a particular area with warning messages about driving conditions. In these systems, multi-hop geocast routing protocols, known to those skilled in the art, are commonly used to extend the reachability of the warning messages, i.e., to deliver active messages to vehicles that may be a few kilometers away, as a one-time multi-hop transmission process. In other words, an initial message advising drivers of a certain situation is transferred from vehicle to vehicle using the geocast routing protocol so that relevant vehicles a significant distance away will receive the messages where one vehicle's direct transmission range is typically relatively short.
Vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2X) applications require a minimum of one entity to send information to another entity. For example, many vehicle-to-vehicle safety applications can be executed on one vehicle by simply receiving broadcast messages from a neighboring vehicle. These messages are not directed to any specific vehicle, but are meant to be shared with a vehicle population to support the safety application. In these types of applications where collision avoidance is desirable, as two or more vehicles talk to each other and a collision becomes probable, the vehicle systems can warn the vehicle drivers, or possibly take evasive action for the driver, such as applying the brakes. Likewise, traffic control units can observe the broadcast of information and generate statistics on traffic flow through a given intersection or roadway.